Repeated human leukocyte antigens eplets, importance of typing the partner.

INTRODUCTION: Antibody-mediated rejection (AMR) is the most common cause of immune-mediated allograft failure after kidney transplant and impacts allograft survival. Previous sensitization is a major risk factor for development of donor specific antibodies (DSA). AMR can have a wide range of clinical features such as impaired kidney function, proteinuria/hypertension or can be subclinical. HLA molecules have specific regions of antigens binding antibodies called epitopes and eplets are considered essential components responsible for immune recognition. We present a patient with subclinical AMR 1 week post transplantation. CASE REPORT: A 48-year-old, caucasian woman with end-stage kidney disease (ESKD) secondary to autosomal dominant polycystic kidney disease (ADPKD) on peritoneal dialysis was registered in deceased donor waitlist. She was a hypersensitized patient from 3 prior pregnancies with a calculated panel reactive antibody of 93,48%. She was transplanted through kidney paired exchange donation with no evidence of DSA pre transplantation. Surgery and post-op were unremarkable with excellent and immediate graft function. Per protocol DSA levels on the 5th day was DR1 of 3300 MFI, with an increase in MFI by day 13 with 7820 MFI and a new B41 1979MFI. Allograft kidney biopsy findings were diagnostic of AMR and she was treated with immunoglobulin and plasmapheresis. As early onset AMR post transplantation was observed an anamnestic response was hypothesized from a previous exposure to allo-HLA. We decided to type her husband, her son's father, which was presented with DSA. Mismatch eplet analysis revealed a shared 41 T and 67LQ eplets between the donor and husband, responsible for the reactivity and new HLA class I B41 and HLA class II DR1 DSA, respectively. DISCUSSION: Shared eplets between the patient husband and donor was responsible for the alloimmune response and early development of DSAs. This case highlights the importance of early monitoring DSA levels in highly sensitized patients after transplant in order to promptly address and lower inflammatory damage. Mismatch eplet analysis can provide a thorough and precise evaluation of immune compatibility providing a useful technique to immune risk stratification, donor selection and post-transplant immunosuppressive therapy and monitoring.

Two Faces of the Same Coin: A Case Report of Antiphospholipid Syndrome Nephropathy.

Antiphospholipid syndrome (APS) is an autoimmune disease which can be primary or secondary to other autoimmune conditions and is defined by the occurrence of arterial or venous thrombosis, or pregnancy morbidity associated with persistently positive antiphospholipid antibodies (aPLA). The kidney may be affected by thrombosis at any level of its vasculature. When small vessels are involved, this results in thrombotic microangiopathy (TMA), which can manifest as either acute vaso-occlusive or chronic vascular lesions in glomeruli, arterioles and interlobular arteries. We report the case of 26-year-old man, with a previous medical history suggestive of APS, who was found to have a small elevation in serum creatinine. A kidney biopsy was performed and revealed features of chronic TMA. Anticoagulation was begun and kidney function remained stable. However, one year later, upon suspension of anticoagulation, the patient developed acute kidney injury and a second kidney biopsy showed acute TMA. This case describes different manifestations of antiphospholipid syndrome nephropathy (APSN) and highlights the importance of anticoagulation for thrombosis prevention. LEARNING POINTS: Antiphospholipid syndrome nephropathy (APSN) can be a difficult diagnosis because (i) antiphospholipid syndrome (APS) is not always clinically evident and (ii) APSN can manifest as subtle histological findings of chronic vascular damage which may be overlooked on a kidney biopsy.Acute kidney injury due to acute thrombotic microangiopathy (TMA) may develop in a patient with chronic TMA, often after a precipitating event. In the case reported here, the most likely trigger was the suspension of anticoagulation after a surgical emergency.Long-term anticoagulation is the mainstay of treatment for both APS and APSN; discontinuing anticoagulation increases the risk of thrombosis and has to be carefully weighed against the risk of serious haemorrhage.